1. Technical Field
The present invention pertains generally to the field of digital televisions and the field of video printers and more particularly, to a system and method for integrating a video printing device and a digital television into a single unit.
2. Background Art
Oftentimes it is desirable to print a hard copy of an image seen on a television during a broadcast. For example, commercials often display address and price information regarding a particular product. Such information, however, is usually displayed only briefly, thus frustrating any attempt by a viewer to write down the information using pencil and paper. Televisions are also frequently being used to incorporate computer functions. Consequently, a user may use the television as a webviewer to access networks, such as the Internet. This increasing use of televisions to integrate computer and television functions further augments the need to be able to print images displayed on the television.
Also of importance is the emergence of digital television, which is revolutionizing the television industry. The current single analog video format having just one resolution and one frame rate is being retired in favor of a multiplicity of digital video formats varying in both resolution and frame rate. This evolution from the present National Television Systems Committee (NTSC) standard to digital television has been compared with the transition from radio to television. Basically, the NTSC standard defines a video frame as containing a total of 525 interlaced lines, such that all the odd lines are scanned before all the even lines at about a 30-Hz frame rate. In contrast, the new Advanced Television Systems Committee (ATSC) standard is more versatile and mandates compressing the video and audio signals as well as using packetized transport for video, audio, and data packets. The resulting compressed video bit stream is modulated for transmission over the air. As a result, the transition from analog NTSC to the compressed digital ATSC high-definition standard completely transforms how a television stores, processes and transmits the new digital television signal. The improved resolution and image quality of digital televisions provide a further incentive for printing high quality images seen on a television.
The prior art has attempted to solve part of this problem through the use of video printers. Conventional video printers allow a user to print a hard copy of an image displayed on a television screen corresponding to a continuous video signal received from a television broadcast. Examples of such video printers are described in U.S. Pat. Nos. 4,626,926 and 5,111,285.
However, conventional video printers suffer from a number of shortcomings. First, conventional video printers are configured to operate in conjunction with televisions based on the analog National Television Systems Committee (NTSC) standard. However, digital televisions based on standards such as the ATSC standard differ significantly from analog NTSC televisions with respect to the signal used, the encoding and decoding of the signal, as well as a myriad of other processing, storage and transmission issues. Consequently, conventional video printers are incapable of operating with digital televisions.
Second, conventional video printers are separate devices which must be attached to a television unit in order to print a hard copy of the television image. As a result, employing a separate printing device to print images from a television increases the space required for the separate television and printer units as well as the inconvenience of and complexity in connecting the separate devices to ensure proper functioning.
Therefore, there is a need for a video printer for digital televisions and more particularly, for a digital television and video printer which are integrated into a single unit.
The present invention is a system and method for integrating a digital television and video printing system into a single unit. The system comprises a buffer (212) for storing the compressed digital video signal (202), a synchronizing means (206) for coordinating the display of the real time digital video signal and the stored digital video signal, a decompressor (214) for decompressing the compressed digital video signal received from the buffer (212) and transmitting it to the synchronizing means (206), a control means (210) for selecting among and printing the images corresponding to the digital video signal stored in the buffer (212), a display means (208) for viewing the real time digital video signal and/or the stored digital video signal, and a printing means (216) for producing a hard copy of the selected image from the buffer.
A real time compressed digital video signal is transmitted to and stored in the buffer. The stored compressed digital video signal is first sent to the decompressor and then is sent to the synchronizing means, which transmits the digital video signal to the display means. A control means allows a user to selectively view on the display the images corresponding to the stored compressed digital video signal and to print the selected image on the printing means.